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Poor man's electronic chromatogram

Posted: Thu Aug 25, 2011 3:11 am
by DJ
We use only strip chart recorders. I've looked into analog/digital converters, software, but the inexpensive ones (clarity) are not compatible with our PE detectors.

I'm not looking to control the instrument from a computer- just the bare minimum= an electronic file of voltage vs time.

Do you think I could route the signal from the detector to oscilloscope, and then dump the data on to a usb?

Re: Poor man's electronic chromatogram

Posted: Thu Aug 25, 2011 2:25 pm
by Peter Skelton
Simplest way? Feed an analog output from your detector into a line in/microphone port on a sound card, then use some sort of audio software to record the incoming signal. You should be able to decode that into numbers using software.

Alternatively, software is available to turn a computer into an oscilliscope using the soundcard as the input. That should work too.

Make sure that you set the voltage output by your detector to an appropriate range for the input you use, or use some sort of attenuator to avoid signal clipping/hardware damage

Re: Poor man's electronic chromatogram

Posted: Thu Aug 25, 2011 3:59 pm
by ScottHorn
There are several cheap USB oscilloscopes on the market. I guess your choice would be based on the software that comes with them. I'm not sure if any of them offer intergration capabilities, but if you can export the data to Excel it wouldn't matter. What kind of outputs does your detector offer? I use the Clarity software with a variety of detectors. As long as it outputs a voltage somewhere, Clarity can read it. They don't explicitly list every possible detector on their website, only the ones that they have written specific drivers for. If you're just dealing with an analog signal there's no need for a driver. The sound card idea would probably be the cheapest way to go though.

Re: Poor man's electronic chromatogram

Posted: Thu Aug 25, 2011 5:33 pm
by sepscientologist
I have used these types of devices with success: http://labjack.com/products?gclid=CK7Gy ... gwoduWL5Mw

Re: Poor man's electronic chromatogram

Posted: Fri Aug 26, 2011 12:59 am
by remesquaddie
We use only strip chart recorders. I've looked into analog/digital converters, software, but the inexpensive ones (clarity) are not compatible with our PE detectors.

I'm not looking to control the instrument from a computer- just the bare minimum= an electronic file of voltage vs time.

Do you think I could route the signal from the detector to oscilloscope, and then dump the data on to a usb?
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What is the detector type, UV/VIS, RI, ? What is the range of signal available out of it, 0-10mv. 0-1volt, 0-10 volts?
WE have sold a lot of Clarity software to collect data, so I am surprised that it cannot handle your detector signal.
You may want to look at the good old integrator if budget is extremely low. If you want to pay for shipping , I have several of these available, free of charge to you.

Re: Poor man's electronic chromatogram

Posted: Sat Aug 27, 2011 5:37 am
by DJ
I have used these types of devices with success: http://labjack.com/products?gclid=CK7Gy ... gwoduWL5Mw

I am looking into this right now. Cannot beat $100. How straight forward is the set-up?

Re: Poor man's electronic chromatogram

Posted: Sat Aug 27, 2011 8:00 pm
by ScottHorn
I looked into the labjack in the past when I was in the same situation. I didn't need to control anything, but I had data from 20+ detectors that needed to be recorded and saved. From what I could glean from the labjack website, they supply you with the interface to do that type of stuff and more, but the software is pretty much up to you. I don't think it comes with anything similar to a chromatography data station to record and analyze the data coming in from the data acquistion unit itself. In a nutshell, if you're really good at programming and electronics in general, you could do a lot with it, but its not a plug-and-play solution. In the end I went with a National Instruments data acquisition device that took something like 18 analog inputs (straight from the outputs on the detector) and transmitted them over wifi. They also offer software that can display the signals in a similar method to a chart recorder, but it costs a little bit more than the basic software package that comes with the device. If I could do it over again I would have bought several stand-alone data logging devices with screens and flash memory (google "paperless chart recorder"). If you've already got a PC, the clarity lite package might be cheaper, especially if you only want to monitor data from a single instrument.

Re: Poor man's electronic chromatogram

Posted: Sun Oct 23, 2011 6:58 pm
by michal
Hi,

If you have a choice to analog output try to buy a analog converter Panther with software ECOMAC.
Try to visit http://www.ecomsro.com/.

Try it.
I had the same problem. Ihave a old UV/VIS detector Dynamax and connect the analog output with serial converter Panther to PC with USB/RS232 cable. Use the ECOM software to decoding/recording of output signal. It is better to manual control of detector ( autozero, wavelenght choice).

Michal